Is it possible to have validation on insert of record that checks if field value exists in another form?

Is it possible to have validation on insert of record that checks if field value exists in another form?

I want to do something like have a validation that on insert of record into a form of field for email address checks if the email address value exists in another form. If the same email address does exist in the other form, I don't want it to consider inserting the new record.

I've been doing some research but still not quite clear if this is possible? Would appreciate any insight. Thanks